Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

Explorer 35 was designed to study interplanetary space phenomena-particularly the solar wind, the interplanetary magnetic field, dust distribution near the Moon, the lunar gravitational field, the weak lunar ionosphere, and the radiation environment.

The spacecraft left Earth on a direct ascent trajectory and entered lunar orbit on 21 July 1967. Initial orbital parameters were 800 x 7,692 kilometers at 147° inclination.

The spacecraft, similar to Explorer 33, also in lunar orbit, found that the Moon has no magnetosphere, that solar wind particles impact directly against the surface, and that the Moon creates a cavity in the solar wind stream.

After six years of successful operation, the satellite was turned off on 24 June 1973. Explorer 35 was launched by the 50th Thor-Delta booster, of which only three had failed, giving the booster a success rating of 94 percent.

Key Dates

19 Jul 1967: Launch (14:19:02 UT)

24 Jun 1973: Spacecraft Shutdown

Status: Successful

Fast Facts

Explorer 35 was launched on the 50th Thor-Delta booster (right), a highly successful launch vehicle of the era.